1. Field of the Invention
The invention relates to a computer-controlled switching apparatus for controlling power switching elements such as relays, motor protection switches or the like, for controlling devices or installations, in which a microprocessor is connected by way of analog-digital converters to at least one sensor, for monitoring the current consumption of the apparatus to be monitored, for example a motor, transformer or the like, the sensor possibly being disposed in the housing of the switching apparatus, and computes characteristic data in accordance with at least one given model and produces switching instructions when parameters rise above or fall below given predetermined values.
2. Description of the Prior Art
A switching element of that kind is known for example from DE-AS No. 26 09 654. In that arrangement, the computer, in accordance with the current values detected, calculates the temperature of the apparatus to be monitored, compares same with a predetermined value and, if necessary, produces a release or triggering signal.
The disadvantage of that known switching apparatus is that it displays the operating condition of the monitored apparatus, at best in regard to the switching condition. In addition, it only provides for a display of the switching condition at the switching apparatus.
However, for larger and more complex installations, it is desirable also to be able to detect the load and temperature condition of the various pieces of equipment being monitored, at a central location. In such an arrangement however, information is to be extracted with the minimum number of lines, in particular main current lines.